Device to be charged and charging method

ABSTRACT

The present disclosure provides a device to be charged and a charging method. The device to be charged includes: a charging interface; a first charging circuit, coupled with the charging interface, configured to receive an output voltage and an output current of an adapter via the charging interface and to directly apply the output voltage and the output current of the adapter to both ends of a plurality of battery cells coupled in series in the device to be charged, so as to perform a direct charging on the plurality of battery cells. With the present disclosure, heat generated in the charging process can be reduced while ensuring the charging speed.

CROSS REFERENCE TO RELATED APPLICATION

This application is a US national phase application of InternationalApplication No. PCT/CN2017/074825, filed on Feb. 24, 2017, which claimspriority to International Application No. PCT/CN2016/101944, filed onOct. 12, 2016, entitled “MOBILE TERMINAL” and International ApplicationNo. PCT/CN2017/073653, filed on Feb. 15, 2017, entitled “DEVICE TO BECHARGED AND CHARGING METHOD”, the entire contents of which areincorporated herein by reference.

TECHNICAL FIELD

The present disclosure generally relates to a charging technical field,and more particularly, to a device to be charged and a charging method.

BACKGROUND

Nowadays, mobile terminals such as smart phones are increasingly favoredby consumers. However, the mobile terminal consumes large power energy,and needs to be charged frequently.

One feasible solution for improving a charging speed is to adopt a largecurrent to charge a device to be charged. The larger the chargingcurrent, the faster the charging speed of the device to be charged.However, the heating problem of the device to be charged becomes seriousaccordingly.

Thus, under the premise of ensuring the charging speed, how to reducethe heat generated in the device to be charged is an urgent problem tobe resolved.

SUMMARY

The present disclosure provides a device to be charged and a chargingmethod, which may reduce the heat generated in the device to be chargedunder the premise of ensuring the charging speed.

Embodiments of the present disclosure provide a device to be charged.The device to be charged includes: a charging interface; a firstcharging circuit, coupled with the charging interface, configured toreceive an output voltage and an output current of an adapter via thecharging interface and to directly apply the output voltage and theoutput current of the adapter to both ends of a plurality of batterycells coupled in series in the device to be charged, so as to perform adirect charging on the plurality of battery cells.

Embodiments of the present disclosure provide a charging method. Thecharging method is applied for charging a device to be charged. Thedevice to be charged includes a charging interface. The charging methodincludes: receiving an output voltage and an output current of anadapter via the charging interface; directly applying the output voltageand the output current of the adapter to both ends of a plurality ofbattery cells coupled in series in the device to be charged, so as toperform a direct charging on the plurality of battery cells; andequalizing voltages of respective battery cells of the plurality ofbattery cells.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic structure diagram illustrating a device to becharged according to an embodiment of the present disclosure.

FIG. 2 is a schematic structure diagram illustrating a device to becharged according to another embodiment of the present disclosure.

FIG. 3 is a schematic structure diagram illustrating a device to becharged according to yet another embodiment of the present disclosure.

FIG. 4 is a schematic structure diagram illustrating a device to becharged according to still another embodiment of the present disclosure.

FIG. 5 is a schematic diagram illustrating a waveform of a pulsatingdirect current according to an embodiment of the present disclosure.

FIG. 6 is a schematic structure diagram illustrating a device to becharged according to still yet another embodiment of the presentdisclosure.

FIG. 7 is a schematic structure diagram illustrating a device to becharged according to still yet another embodiment of the presentdisclosure.

FIG. 8 is a schematic structure diagram illustrating a device to becharged according to still yet another embodiment of the presentdisclosure.

FIG. 9 is a schematic diagram illustrating a charging process accordingto an embodiment of the present disclosure.

FIG. 10 is a schematic flow chart illustrating a charging methodaccording to an embodiment of the present disclosure.

FIG. 11 is a schematic structure diagram illustrating an equalizationcircuit according to an embodiment of the present disclosure.

FIG. 12 is a schematic structure diagram illustrating an equalizationcircuit according to another embodiment of the present disclosure.

FIG. 13 is a schematic structure diagram illustrating an equalizationcircuit according to yet another embodiment of the present disclosure.

FIG. 14 is a schematic structure diagram illustrating an equalizationcircuit according to still another embodiment of the present disclosure.

FIG. 15 is a schematic circuit diagram illustrating an equalizationcircuit according to an embodiment of the present disclosure.

FIG. 16 is a schematic circuit diagram illustrating an equalizationcircuit according to another embodiment of the present disclosure.

DETAILED DESCRIPTION

Before describing a device to be charged and a charging method accordingto embodiments of the present disclosure, an adapter for charging thedevice to be charged in the related art (hereinafter, “related adapter”)will be described.

Voltage outputted by the related adapter is basically constant, such as5V, 9V, 12V or 20V or the like, when the related adapter works in aconstant voltage mode.

The voltage outputted by the related adapter is unsuitable for beingdirectly applied to both ends of a battery. It is required to convertthe voltage by a conversion circuit in the device to be charged toobtain a charging voltage and/or charging current expected by thebattery in the device to be charged. The charging current may be adirect current.

The conversion circuit is configured to convert the voltage outputted bythe related adapter, to meet a requirement of the charging voltageand/or charging current expected by the battery.

As an example, the conversion circuit may be a charging managementmodule, such as a charging integrated circuit (IC) in the device to becharged. During a charging process of the battery, the conversioncircuit may be configured to manage the charging voltage and/or chargingcurrent of the battery. The conversion circuit may have at least one ofa voltage feedback function and a current feedback function, so as tomanage the charging voltage and/or charging current of the battery.

For example, the charging process of the battery may include at leastone of a trickle charging stage, a constant current charging stage and aconstant voltage charging stage. In the trickle charging stage, theconversion circuit may utilize a current feedback loop to ensure that acurrent flowing into the battery in the trickle charging stage meets thecharging current (such as a first charging current) expected by thebattery. In the constant current charging stage, the conversion circuitmay utilize a current feedback loop to ensure that the current flowinginto the battery in the constant current charging stage meets thecharging current (such as a second charging current, which may begreater than the first charging current) expected by the battery. In theconstant voltage charging stage, the conversion circuit may utilize avoltage feedback loop to ensure that a voltage applied to both ends ofthe battery in the constant voltage charging stage meets the chargingvoltage expected by the battery.

As an example, when the voltage outputted by the related adapter isgreater than the charging voltage expected by the battery, theconversion circuit may be configured to perform a buck conversion on thevoltage outputted by the related adapter to enable a buck-convertedcharging voltage to meet the requirement of the charging voltageexpected by the battery. As another example, when the voltage outputtedby the related adapter is less than the charging voltage expected by thebattery, the conversion circuit may be configured to perform a boostconversion on the voltage outputted by the related adapter to enable aboost-converted charging voltage to meet the requirement of the chargingvoltage expected by the battery.

As another example, assume that the related adapter outputs a constantvoltage of 5V. When the related adapter charges a single battery cell(such as a lithium battery cell, a charging cut-off voltage of a singlebattery cell is typically 4.2V), the conversion circuit (for example, abuck circuit) may perform a buck conversion on the voltage outputted bythe related adapter, such that the charging voltage obtained after thebuck conversion meets a requirement of the charging voltage expected bythe single battery cell.

As yet another example, assume that the related adapter outputs aconstant voltage of 5V. When the related adapter charges a plurality of(two or more) battery cells (such as lithium battery cell, a chargingcut-off voltage of a single battery cell is typically 4.2V) coupled inseries, the conversion circuit (for example, a boost circuit) mayperform a boost conversion on the voltage outputted by the relatedadapter, such that the charging voltage obtained after the boostconversion meets a requirement of the charging voltage expected by theplurality of battery cells.

Limited by a poor conversion efficiency of the conversion circuit, apart of electric energy is lost in a form of heat, and the heat maygather inside the device to be charged. A design space and a space forheat dissipation of the device to be charged are small (for example, thephysical size of a mobile terminal used by a user becomes thinner andthinner, while plenty of electronic elements are densely arranged in themobile terminal to improve performance of the mobile terminal), whichnot only increases difficulty in designing the conversion circuit, butalso results in that it is hard to dissipate the heat gathered in thedevice to be charged in time, thus further causing an abnormity of thedevice to be charged.

For example, the heat gathered on the conversion circuit may cause athermal interference on electronic elements neighboring the conversioncircuit, thus causing abnormal operations of the electronic elements.For another example, the heat gathered on the conversion circuit mayshorten the service life of the conversion circuit and neighboringelectronic elements. For yet another example, the heat gathered on theconversion circuit may cause a thermal interference on the battery, thuscausing abnormal charging and/or abnormal discharging of the battery.For still another example, the heat gathered on the conversion circuitmay increase the temperature of the device to be charged, thus affectinguser experience during the charging. For still yet another example, theheat gathered on the conversion circuit may short-circuit the conversioncircuit, such that the voltage outputted by the related adapter isdirectly applied to both ends of the battery, thus causing anover-voltage charging of the battery, which brings safety hazard if theover-voltage charging lasts for a long time, for example, the batterymay explode.

The adapter according to embodiments of the present disclosure mayobtain status information of the battery. The status information of thebattery at least includes electric quantity information and/or voltageinformation of the battery. The adapter adjusts the voltage outputted byitself according to the obtained status information of the battery, tomeet the requirement of the charging voltage and/or charging currentexpected by the battery. The output voltage after the adjustment may bedirectly applied to both ends of the battery for charging the battery(hereinafter, “direct charging”). The voltage outputted by the adaptermay be a voltage with a stable voltage value or a voltage with apulsating waveform.

The adapter may have a voltage feedback function and/or a currentfeedback function, so as to realize a closed-loop feedback control onthe charging voltage and/or charging current of the battery.

In some embodiments, the adapter may adjust the voltage outputted byitself according to the obtained status information of the battery asfollows. The adapter may obtain the status information of the battery inreal time, and adjust the voltage outputted by itself according to thestatus information of the battery obtained in real time, to meet thecharging voltage and/or charging current expected by the battery.

In some embodiments, the adapter may adjust the voltage outputted byitself according to the status information of the battery obtained inreal time as follows. During the charging process, with the increasingof the charging voltage of the battery, the adapter may obtain statusinformation of the battery at different time points in the chargingprocess, and adjust the voltage outputted by itself in real timeaccording to the status information of the battery at different timepoints in the charging process, to meet the requirement of the chargingvoltage and/or charging current expected by the battery. The outputvoltage after the adjustment of the adapter may be directly applied toboth ends of the battery to charge the battery.

For example, the charging process of the battery may include at leastone of a trickle charging stage, a constant current charging stage and aconstant voltage charging stage. In the trickle charging stage, theadapter may output the first charging current (the first chargingcurrent may be a constant direct current or a current with a pulsatingwaveform) to charge the battery, so as to meet the requirement of thecharging current expected by the battery. In the constant currentcharging stage, the adapter may utilize a current feedback loop toensure that the current outputted by the adapter and flowing into thebattery in the constant current charging stage meets the requirement ofthe charging current expected by the battery (such as a second chargingcurrent, which may be a constant direct current or a current with apulsating waveform, and may be greater than the first charging current.For example, when the second charging current is a current with apulsating waveform, the second charging current being greater than thefirst charging current means that, a peak value of the current with thepulsating waveform in the constant current charging stage is greaterthan that of the current with the pulsating waveform in the tricklecharging stage, while “constant current” of the constant currentcharging stage means that, in the constant current charging stage, apeak value or a mean value of the current with the pulsating waveform isbasically constant). In the constant voltage charging stage, the adaptermay utilize a voltage feedback loop to ensure that a voltage (i.e., avoltage with a pulsating waveform) outputted by the adapter to thedevice to be charged within the constant voltage charging stage isconstant.

For example, the adapter according to embodiments of the presentdisclosure is mainly configured to control the constant current chargingstage of the battery in the device to be charged. In other embodiments,the control on the trickle charging stage and the constant voltagecharging stage of the battery in the device to be charged can berealized by the adapter according to embodiments of the presentdisclosure in coordination with an additional charging chip in thedevice to be charged. Compared to the constant current charging stage,the charging power received by the battery in the trickle charging stageand the constant voltage charging stage is smaller, such that theconversion loss and heat accumulation of the charging chip in the deviceto be charged is acceptable. In some embodiments, the constant currentcharging stage or the constant current mode involved in embodiments ofthe present disclosure may refer to a charging stage or a charging modein which the current outputted by the adapter is controlled. It isunnecessary to keep the current outputted by the adapter completelyconstant. For example, when the current outputted by the adapter is acurrent with a pulsating waveform, the constant current may refer tothat, a peak value or a mean value of the current with the pulsatingwaveform outputted by the adapter is basically constant, or keepsconstant during a certain time period. For example, in practice, theadapter typically adopts a multi-stage constant current mode forcharging in the constant current charging stage.

The multi-stage constant current charging may include M constant currentstages, where M is an integer no less than 2. The first charging stageof the multi-stage constant current charging starts with a predeterminedcharging current. M constant current stages in the multi-stage constantcurrent charging are performed in sequence from the first charging stageto the (M−1)^(th) charging stage. After the constant current charging isswitched from one constant current stage to the next constant currentstage, the peak value or mean value of the current with the pulsatingwaveform may be decreased. When the battery voltage reaches a chargingstop voltage threshold, the constant current charging is switched fromthe present constant current stage to the next constant current stage.The current change between two adjacent constant current stages may begradual, or may be in a stepped skip manner.

Further, it should be noted that, the device to be charged according toembodiments of the present disclosure may, for example, be a terminal ora communication terminal. The terminal or the communication terminalincludes, but is not limited to a device configured to receive/transmitcommunication signals via a wired connection (for example, publicswitched telephone network (PSTN), digital subscriber line (DSL)connection, digital cable connection, direct cable connection and/oranother data connection/network) and/or via a wireless interface (forexample, cellular network, wireless local area network (WLAN), digitalTV network such as digital video broadcasting handheld (DVB-H) network,satellite network, an amplitude modulation-frequency modulation (AM-FM)broadcasting transmitter, and/or a wireless interface of anothercommunication terminal). The communication terminal configured tocommunicate via the wireless interface may be referred to as “wirelesscommunication terminal”, “wireless terminal” and/or “mobile terminal”.Examples of a mobile terminal include, but are not limited to asatellite phone or a cell phone, a terminal combining a cell radio phoneand a personal communication system (PCS) having capability of dataprocess, fax, and data communication, a personal digital assistant (PDA)including a radio phone, a pager, Internet/Intranet access, a webbrowser, a note pad & address book, a calendar and/or a globalpositioning system (GPS) receiver, and a common laptop and/or handheldreceiver, or other electronic devices including a radio phonetransceiver.

In addition, in embodiments of the present disclosure, when the voltagewith the pulsating waveform outputted by the adapter is directly appliedto both ends of the battery in the device to be charged to charge thebattery, the charging current may be characterized by a pulsatingwaveform such as a steamed bun waveform. In some embodiments, thecharging current may be used to charge the battery intermittently. Aperiod of the charging current may vary with a frequency of an inputalternating current (such as a frequency of an alternating current powergrid). For example, the frequency corresponding to the period of thecharging current may be an integral multiple or a fraction of thefrequency of the power grid. Moreover, when the charging current is usedto charge the battery intermittently, a current waveform correspondingto the charging current may be formed of one pulse or a set of pulsessynchronous to the power grid.

As an example, during the charging process (such as, at least one of thetrickle charging stage, the constant current charging stage and theconstant voltage charging stage), the battery may receive the pulsatingdirect current (having a direction unchanged and amplitude varying withtime), the alternating current (having a direction and amplitude bothvarying with time) or the constant direct current (having a directionand amplitude both unchanged) outputted by the adapter.

In the related art, the device to be charged typically includes only asingle battery cell. When the single battery cell is charged with largecharging current, a serious heating phenomenon occurs on the device tobe charged. In order to ensure the charging speed of the device to becharged and relieve the heating phenomenon on the device to be chargedduring the charging, the structure of the battery cell in the device tobe charged according to embodiments of the present disclosure isimproved by incorporating a plurality of battery cells coupled inseries, and a direct charging is performed on the plurality of batterycells. Embodiments of the present disclosure will be described in detailwith reference to FIG. 1.

FIG. 1 is a schematic structure diagram illustrating a device to becharged according to embodiments of the present disclosure. The device10 to be charged in FIG. 1 includes a charging interface 11 and a firstcharging circuit 12. The first charging circuit 12 is coupled with thecharging interface 11. The first charging circuit 12 receives an outputvoltage and an output current of an adapter via the charging interface11, and directly applies the output voltage and the output current ofthe adapter to both ends of the plurality of battery cells 13 coupled inseries in the device to be charged so as to perform a direct charging onthe plurality of battery cells 13.

In order to solve the heating problem due to a conversion circuit and toreduce power consumption, in embodiments of the present disclosure, theplurality of battery cells 13 are charged in a direct charging mannervia the first charging circuit 12.

The solution of direct charging can reduce the heat generated in thedevice to be charged to some extent. However, when the output current ofthe adapter is too large, for example, when the output current of theadapter reaches a value ranging from 5 A to 10 A, the device to becharged may have a serious heating problem, thus causing a safetyhazard. In order to ensure the charging speed and to further relieve theheating phenomenon of the device to be charged, in embodiments of thepresent disclosure, the structure of the battery cell in the device tobe charged is further improved, i.e., the plurality of battery cellscoupled in series are incorporated. Compared to the solution of a singlebattery cell, to achieve the same charging speed, the charging currentrequired by the plurality of battery cells is 1/N (N is the number ofthe plurality of battery cells coupled in series in the device to becharged) of that required by the single battery cell. In other words,under the premise of the same charging speed, the charging current maybe reduced greatly in embodiments of the present disclosure, thusfurther reducing the heat generated during the charging process in thedevice to be charged.

For example, for the single battery cell of 3000 mAh, a charging currentof 9 A is required to reach a charging rate of 3 C. In order to reachthe same charging speed and to reduce the heat generated during thecharging process in the device to be charged, two battery cells each ofwhich is 1500 mAh may be coupled in series, so as to replace a singlebattery cell of 3000 mAh. In this way, it merely requires a chargingcurrent of 4.5 A to reach the charging rate of 3 C. Compared to acharging current of 9 A, the charging current of 4.5 A causes obviouslyless heat.

In some embodiments, since the first charging circuit 12 charges theplurality of battery cells 13 in the direct charging manner, the outputvoltage received by the first charging circuit 12 from the adapter needsto be greater than a total voltage of the plurality of battery cells 13.Generally, a working voltage of a single battery cell is typicallywithin 3.0V-4.35V. For example, for two battery cells coupled in series,the output voltage of the adapter may be greater than or equal to 10 V.

In some embodiments, a type of the charging interface 11 is not limitedin embodiments of the present disclosure. For example, the charginginterface 11 may be a universal serial bus (USB) interface, which may bea common USB interface or a micro USB interface, or a Type-C interface.The first charging circuit 12 may charge the plurality of battery cells13 via a power wire in the USB interface. The power wire in the USBinterface may be a VBus wire and/or a ground wire in the USB interface.

The plurality of battery cells 13 in embodiments of the presentdisclosure may include battery cells with the same or similarspecification and parameters. The battery cells with the same or similarspecification are easy to manage. The overall performance and servicelife of the plurality of battery cells 13 can be improved when batterycells with the same or similar specification and parameters areselected.

In some embodiments, the plurality of battery cells 13 coupled in seriescan realize voltage-dividing on the output voltage of the adapter.

In the related art, the device to be charged (or elements in the deviceto be charged, or a chip in the device to be charged) typically adopts asingle battery cell for power supply. In embodiments of the presentdisclosure, the plurality of battery cells coupled in series areincorporated, which have a high total voltage unsuitable for being usedto supply power for the device to be charged (or elements in the deviceto be charged, or a chip in the device to be charged) directly. Forsolving this problem, one feasible implementation is to adjust theworking voltage of the device to be charged (or elements in the deviceto be charged, or a chip in the device to be charged) to support thepower supply of the plurality of battery cells. However, with thisimplementation, the device to be charged needs to be changed greatly,thus causing a high cost. In the following, an implementation accordingto embodiments of the present disclosure is described in detail withreference to FIG. 2 and FIG. 3, in which the problem of how to supplypower using the plurality of battery cells can be solved.

In some embodiments, as illustrated in FIG. 2, the device 10 to becharged further includes a step-down circuit 21 and a power supplycircuit 22. An input end of the step-down circuit 21 is coupled to bothends of the plurality of battery cells 13 respectively. The step-downcircuit 21 is configured to convert the total voltage of the pluralityof battery cells 13 into a first voltage V1, where a≤V1≤b, a representsthe minimum working voltage of the device 10 to be charged (or elementsin the device 10 to be charged, or a chip in the device 10 to becharged), and b represents the maximum working voltage of the device 10to be charged (or elements in the device 10 to be charged, or a chip inthe device 10 to be charged). The power supply circuit 22 is coupled toan output end of the step-down circuit 21. The power supply circuit 22supplies power for the device 10 to be charged based on the firstvoltage.

In embodiments of the present disclosure, the step-down circuit 21 isincorporated on the basis of the embodiment described with regard toFIG. 1. When the device to be charged is in a working state, the totalvoltage of the plurality of battery cells 13 is stepped down by thestep-down circuit 21 to obtain a first voltage. Since the first voltageis between the minimum working voltage and the maximum working voltageof the device 10 to be charged, the first voltage can be directly usedto supply power for the device to be charged, thus solving the problemof how to supply power using the plurality of battery cells.

In some embodiments, the total voltage of the plurality of battery cells13 varies with the electric quantity of the plurality of battery cells13. The aforementioned total voltage of the plurality of battery cells13 may refer to a present total voltage of the plurality of batterycells 13. For example, the working voltage of a single battery cell isin a range of 3.0V-4.35V. Assuming that the plurality of battery cellsinclude two battery cells and the present voltage of each battery cellis 3.5V, the aforementioned total voltage of the plurality of batterycells 13 is 7V.

For example, the working voltage of the single battery cell is in arange of 3.0V-4.35V, i.e., a=3.0V and b=4.35V. In order to ensure thatthe power supply voltage of elements in the device to be charged isnormal, the step-down circuit 21 may step down the total voltage of theplurality of battery cells 13 to any value in the range of 3.0V-4.35V.There are many ways to implement the step-down circuit 21, for example,a buck circuit, a charge pump or the like can be used for stepping downvoltage.

In some embodiments, for simplifying the implementation of a circuit,the step-down circuit 21 may be a charge pump. With the charge pump, thetotal voltage of the plurality of battery cells 13 may be directlystepped down to 1/N of the present total voltage, where N is the numberof the plurality of battery cells 13. A conventional buck circuitincludes a switch transistor, an inductor and other elements. Since thepower consumption of the inductor is large, the power consumption ishigh when the buck circuit is used to buck voltage. Compared to the buckcircuit, the charge pump mainly utilizes a switch transistor and acapacitor to buck voltage, and the capacitor does not consume additionalenergy basically. Thus, the power consumption during the step-downprocess can be decreased when the charge pump is used. In detail, theswitch transistor in the charge pump controls the charging anddischarging of the capacitor in a certain manner, such that the inputvoltage is stepped down by a certain factor (in embodiments of thepresent disclosure, the factor is 1/N), and the desired voltage can beobtained.

In some embodiments, as illustrated in FIG. 3, the device 10 to becharged further includes a power supply circuit 32. An input end of thepower supply circuit 32 is coupled to both ends of any one of theplurality of battery cells 13. The power supply circuit 32 suppliespower for the elements in the device 10 to be charged based on thevoltage of a single battery cell 13.

In some embodiments, the voltage after the buck conversion of thestep-down circuit may have a pulsating wave, thus affecting the qualityof power supply of the device to be charged. In embodiments of thepresent disclosure, the power supply voltage is derived from both endsof one of the plurality of battery cells 13 directly to supply power forelements in the device to be charged. Since the voltage outputted by thebattery cell is stable relatively, in embodiments of the presentdisclosure, not only the problem of how to supply power using theplurality of battery cells can be solved but also the quality of powersupply of the device to be charged can be guaranteed.

Further, on the basis of the embodiment described with regard to FIG. 3,as illustrated in FIG. 4, the device 10 to be charged further includesan equalization circuit 33. The equalization circuit 13 is coupled withthe plurality of battery cells 13. The equalization circuit 13 isconfigured to equalize voltages of respective battery cells of theplurality of battery cells 13.

When the power supply mode illustrated in FIG. 3 is adopted, the batterycell that supplies power for the elements in the device to be charged(hereinafter, this battery cell is referred to as a main battery cell,and other battery cells are referred as slave battery cells) consumeelectric quantity constantly, such that the voltage of the main batterycell and the voltage of the salve battery cell are not equalized (or,the voltage of the main battery cell and the voltage of the slavebattery cell are inconsistent). The overall performance of the pluralityof battery cells 13 is decreased when the voltages of respective batterycells 13 are not equalized, thus affecting the service life of theplurality of battery cells 13. In addition, it is hard to manage theplurality of battery cells 13 when the voltages of respective batterycells 13 are not equalized. Thus, in embodiments of the presentdisclosure, the equalization circuit 33 is introduced, to equalize thevoltages of respective cells of the plurality of battery cells 13, thusimproving the overall performance of the plurality of battery cells 13and facilitating the unified management of the plurality of batterycells 13.

There are many ways to implement the equalization circuit 33. Forexample, a load may be coupled to both ends of the slave battery cell toconsume the electric quantity of the slave battery cell, such that theelectric quantity of the slave battery cell may be consistent with theelectric quantity of the main battery cell. In an embodiment, the slavebattery cell may be used to charge the main battery cell, until thevoltage of the main battery cell is consistent with the voltage of theslave battery cell.

As an example, the plurality of battery cells 13 may include a firstbattery cell 131 and a second battery cell 132 (see FIG. 15). Theequalization circuit 33 is configured to transfer electric quantitybetween the first battery cell and the second battery cell in anelectromagnetic coupling manner.

In embodiments of the present disclosure, the equalization circuit isconfigured to equalize the voltages of respective battery cells in theelectromagnetic coupling manner, such that the overall performance ofthe plurality of battery cells 13 is improved and it is convenient tomanage the plurality of battery cells 13.

In an embodiment, the first battery cell 131 may be the slave batterycell and the second battery cell 132 may be the main battery cell. Thefirst battery cell 131 may transfer electric quantity to the secondbattery cell 132 via the equalization circuit 33.

In an embodiment, each of the first battery cell 131 and the secondbattery cell 132 may include one battery cell or may include at leasttwo battery cells, which is not limited herein.

In an embodiment, when each of the first battery cell 131 and the secondbattery cell 132 includes one battery cell, the first battery cell 131may be any one of the plurality of battery cells 13, and the secondbattery cell 132 may be any battery cell other than the first batterycell 131 in the plurality of battery cells 13.

As an example, as illustrated in FIG. 11, the equalization circuit 33may include a first circuit 41 and a second circuit 42. The firstcircuit 41 is coupled with the first battery cell 131, and the secondcircuit 42 is coupled with the first battery cell 131 and the secondbattery cell 132 respectively. When the first circuit 41 is switched on,the first circuit 41 is configured to couple energy outputted by thefirst battery cell 131 to the second circuit 42 in an electromagneticcoupling manner, such that the second circuit 42 generates a firstcharging current based on the energy from the first circuit 41, andcharges the first battery cell and the second battery cell with thefirst charging current.

In embodiments of the present disclosure, the first circuit 41 in theequalization circuit 33 couples the energy outputted by the firstbattery cell 131 to the second circuit 42, and the second circuit 42generates the first charging current based on the energy from the firstcircuit 41, and charges the first battery cell 131 and the secondbattery cell 132 with the first charging current. When the first circuitis switched on, the equalization circuit 33 transfers the energyobtained from the first battery cell 131 to the first battery cell 131and the second battery cell 132, so as to realize an electric quantitytransfer between the first battery cell 131 and the second battery cell132.

In an embodiment, as illustrated in FIG. 12, the equalization circuit 33further includes a third circuit 43. The third circuit 43 is coupledwith the second battery cell 132. When the third circuit 43 is switchedon, the third circuit 43 is configured to couple energy outputted by thesecond battery cell 132 to the second circuit 42 in an electromagneticcoupling manner, such that the second circuit 42 generates a secondcharging current based on the energy from the third circuit 43, andcharges the first battery cell 131 and the second battery cell 132 withthe second charging current.

In embodiments of the present disclosure, when the third circuit 43 isswitched on, the equalization circuit 33 can also transfer the energyobtained from the second battery cell 132 to the first battery cell 131and the second battery cell 132, so as to realize the electric quantitytransfer between the first battery cell 131 and the second battery cell132.

In an embodiment, in an example illustrated in FIG. 12, when the voltageof the first battery cell 131 is greater than that of the second batterycell 132, the first circuit 41 and the second circuit 42 may be switchedon, and the third circuit 43 may be switched off, such that the energyof the first battery cell 131 is transferred to the first battery cell131 and the second battery cell 132. When the voltage of the secondbattery cell 132 is greater than that of the first battery cell 131, thefirst circuit 41 may be switched off, and the second circuit 42 and thethird circuit 43 may be switched on, such that the energy of the secondbattery cell 132 is transferred to the first battery cell 131 and thesecond battery cell 132. In this way, voltage equalization of respectivebattery cells can be realized.

FIG. 13 is a schematic structure diagram illustrating an equalizationcircuit according to another embodiment of the present disclosure. Asillustrated in FIG. 13, the equalization circuit 33 includes a fourthcircuit 44 and a fifth circuit 45. The fourth circuit 44 is coupled withthe first battery cell 131 and the second battery cell 132 respectively,and the fifth circuit 45 is coupled with the first battery cell 131.When both the fourth circuit 44 and the fifth circuit 45 are switchedon, the fourth circuit 44 is configured to couple energy outputted bythe first battery cell 131 and the second battery cell 132 to the fifthcircuit 45 in an electromagnetic coupling manner, such that the fifthcircuit 45 generates a second charging current based on the energy fromthe fourth circuit 44, and charges the first battery cell 131 with thesecond charging current.

In embodiments of the present disclosure, the fourth circuit 44 in theequalization circuit 33 couples the energy outputted by the firstbattery cell 131 and the second battery cell 132 to the fifth circuit45, and the fifth circuit 45 generates the second charging current basedon the energy from the fourth circuit 44, and charges the first batterycell 131 with the second charging current. When the fourth circuit 44 isswitched on, the equalization circuit 33 transfers the energy obtainedfrom the first battery cell 131 and the second battery cell 132 to thefirst battery cell 131, so as to realize an electric quantity transferbetween the first battery cell 131 and the second battery cell 132.

In an embodiment, as illustrated in FIG. 14, the equalization circuit 33further includes a sixth circuit 46. The sixth circuit 46 is coupledwith the second battery cell 132. When both the fourth circuit 44 andthe sixth circuit 46 are switched on, the fourth circuit 44 isconfigured to couple energy outputted by the first battery cell 131 andthe second battery cell 132 to the sixth circuit 46 in anelectromagnetic coupling manner, such that the sixth circuit 46generates a third charging current based on the energy from the fourthcircuit 44, and charges the second battery cell 132 with the thirdcharging current.

In embodiments of the present disclosure, when the sixth circuit 46 isswitched on, the equalization circuit 33 can transfer the energyobtained from the first battery cell 131 and the second battery cell 132to the second battery cell 132, so as to realize the electric quantitytransfer between the first battery cell 131 and the second battery cell132.

In an embodiment, in an example illustrated in FIG. 14, when the voltageof the second battery cell 132 is greater than that of the first batterycell 131, the fourth circuit 44 and the fifth circuit 45 may be switchedon, and the sixth circuit 46 may be switched off, such that the energyof the first battery cell 131 and the second battery cell 132 istransferred to the first battery cell 131. When the voltage of the firstbattery cell 131 is greater than that of the second battery cell 132,the fifth circuit 45 may be switched off, and the fourth circuit 44 andthe sixth circuit 46 may be switched on, such that the energy of thefirst battery cell 131 and the second battery cell 132 is transferred tothe second battery cell 132. In this way, voltage equalization ofrespective battery cells can be realized.

FIG. 15 is a circuit schematic illustrating an equalization circuitaccording to an embodiment of the present disclosure. As illustrated inFIG. 15, the first circuit 41 may include a first inductor M1 and aswitch transistor Q1. The second circuit 42 may include a secondinductor M2 and a rectifier diode. The third circuit 43 may include athird inductor M3 and a switch transistor Q2. The first inductor M1 andthe second inductor M2 are coupled with each other, and the secondinductor M2 and the third inductor M3 are coupled with each other.

In an example illustrated in FIG. 15, the switch transistor Q1 or theswitch transistor Q2 may be configured to generate a pulse current.

For example, when the switch transistor Q1 works and the switchtransistor Q2 is switched off, the equalization circuit 33 may transferthe electric quantity of the first battery cell 131 to the first batterycell 131 and the second battery cell 132 in an electromagnetic couplingmanner.

Similarly, when the switch transistor Q2 works and the switch transistorQ1 is switched off, the equalization circuit 33 may transfer theelectric quantity of the second battery cell 132 to the first batterycell 131 and the second battery cell 132 in an electromagnetic couplingmanner.

FIG. 16 is a circuit schematic illustrating an equalization circuitaccording to another embodiment of the present disclosure. Asillustrated in FIG. 16, the fourth circuit 44 may include a fourthinductor M4 and a switch transistor Q4. The fifth circuit 45 may includea fifth inductor M5 and a switch transistor Q5. The sixth circuit 46 mayinclude a sixth inductor M6 and a switch transistor Q6. The fourthinductor M4 and the fifth inductor M5 are coupled with each other, andthe fourth inductor M4 and the sixth inductor M6 are coupled with eachother.

In an example illustrated in FIG. 16, the switch transistor Q4 isconfigured to generate a pulse current. The switch transistor Q5 isconfigured to control the fifth circuit 45 to switch on or off and theswitch transistor Q6 is configured to control the sixth circuit 46 toswitch on or off.

For example, when the switch transistor Q4 works, the switch transistorQ5 is switched on, and the switch transistor Q6 is switched off, theequalization circuit 33 may transfer the electric quantity of the firstbattery cell 131 and the second battery cell 132 to the first batterycell 131 in an electromagnetic coupling manner.

Similarly, when the switch transistor Q4 works, the switch transistor Q5is switched off, and the switch transistor Q6 is switched on, theequalization circuit 33 may transfer the electric quantity of the firstbattery cell 131 and the second battery cell 132 to the second batterycell 132 in an electromagnetic coupling manner.

As the output power of the adapter increases, a lithium precipitationmay occur when the adapter charges the battery cell in the device to becharged, thus shortening the service life of the battery cell.

In order to improve the reliability and safety of the battery cell, insome embodiments, the adapter may be controlled to output a pulsatingdirect current (or called as a unidirectional pulsating output current,or called as a current with a pulsating waveform, or called as a steamedbun current). Since the first charging circuit 12 charges the pluralityof battery cells 13 in a direct charging manner, the pulsating directcurrent outputted by the adapter may be directly applied to both ends ofthe plurality of battery cells 13. As illustrated in FIG. 5, themagnitude of the pulsating direct current changes periodically. Comparedto the constant direct current, the pulsating direct current may reducethe lithium precipitation and improve the service life of the batterycell. In addition, compared to the constant direct current, thepulsating direct current may reduce a probability and intensity of arcdischarge of a contact of a charging interface and improve the servicelife of the charging interface.

There are many ways to set the output current of the adapter as thepulsating direct current. For example, a primary filter circuit and asecondary filter circuit may be removed from the adapter, such that theobtained output current of the adapter is the pulsating direct current.

In some embodiments, the output current of the adapter received by thefirst charging circuit 12 may be an alternating current (for example,the primary filter circuit, a secondary rectifier circuit and thesecondary filter circuit are removed from the adapter, and then theobtained output current of the adapter is the alternating current),which also can reduce the lithium precipitation and improve the servicelife of the battery cell.

In some embodiments, the output voltage and the output current of theadapter received by the first charging circuit 12 via the charginginterface 11 may be a voltage and a current outputted by the adapter ina constant current mode (the constant current charging mode or theconstant current charging stage) respectively.

In some embodiments, as illustrated in FIG. 6, the plurality of batterycells 13 may be encapsulated in one battery 51. Further, the battery 51may include a battery protection plate 52, by means of whichover-voltage and over-current protection, electric quantity balancemanagement and electric quantity management or the like may be realized.

In some embodiments, the plurality of battery cells 13 may beencapsulated in a plurality of batteries.

In some embodiments, as illustrated in FIG. 7, the device 10 to becharged may further include a second charging circuit 61. The secondcharging circuit 61 may include a step-up circuit 62. The step-upcircuit 62 has both ends coupled to the charging interface 11 and theplurality of battery cells 13 respectively. The step-up circuit 62 mayreceive the output voltage of the adapter via the charging interface 11,step up the output voltage of the adapter to a second voltage, and applythe second voltage to both ends of the plurality of battery cells 13 tocharge the plurality of battery cells 13. The output voltage of theadapter received by the second charging circuit 61 is less than thetotal voltage of the plurality of battery cells 13, and the secondvoltage is greater than the total voltage of the plurality of batterycells 13.

It can be seen that, the first charging circuit 12 charges the pluralityof battery cells 13 in a direct charging manner. In the direct chargingmanner, it is required that the output voltage of the adapter is greaterthan the total voltage of the plurality of battery cells 13. Forexample, in a case that two battery cells are coupled in series, if thepresent voltage of each battery cell is 4V, it is required that theoutput voltage of the adapter is at least greater than 8V when the firstcharging circuit 12 is used to charge the two battery cells. However, anoutput voltage of a normal adapter (such as the related adapter abovementioned) is typically 5V, which is unable to charge the plurality ofbattery cells 13 via the first charging circuit 12. For compatibilitywith the normal adapter, the second charging circuit 61 is incorporatedin embodiments of the present disclosure, and the second chargingcircuit 61 includes the step-up circuit 62 which may step up the outputvoltage of the adapter to the second voltage greater than the totalvoltage of the plurality of battery cells 13, such that the problem thatthe normal adapter cannot charge the plurality of battery cells 13coupled in series is solved.

The voltage value of the output voltage of the adapter received by thesecond charging circuit 61 is not limited in embodiments of the presentdisclosure, as long as the output voltage of the adapter is less thanthe total voltage of the plurality of battery cells 13, and theplurality of battery cells 13 can be charged after the output voltage ofadapter is stepped up by the second charging circuit 61.

The specific form of the step-up circuit is not limited in embodimentsof the present disclosure. For example, a boost circuit or a charge pumpcan be used to boost the voltage. In some embodiments, the secondcharging circuit 61 may be designed as a conventional charging circuit,i.e., a conversion circuit (such as a charging IC) is disposed betweenthe charging interface and the battery cell. The conversion circuit mayperform a constant voltage and constant current control on the chargingprocess of the adapter, and adjust the output voltage of the adapteraccording to actual situations, for example, boost or buck voltage. Inembodiments of the present disclosure, the voltage boost function of theconversion circuit is used for boosting the output voltage of theadapter to the second voltage greater than the total voltage of theplurality of battery cells 13. In some embodiments, a switching betweenthe first charging circuit 12 and the second charging circuit 61 may berealized via a switch or a control unit. For example, the control unitis disposed inside the device to be charged. The control unit may switchbetween the first charging circuit 12 and the second charging circuit 61flexibly according to actual requirements, such as according to a typeof the adapter.

In some embodiments, the adapter supports a first charging mode and asecond charging mode. The charging speed at which the adapter chargesthe device to be charged in the second charging mode is faster than thecharging speed at which the adapter charges the device to be charged inthe first charging mode.

In some embodiments, in the first charging mode, the adapter charges theplurality of battery cells 13 via the second charging circuit 61. In thesecond charging mode, the adapter charges the plurality of battery cells13 via the first charging circuit 12. In other words, compared to theadapter working in the first charging mode, the adapter working in thesecond charging mode can fully charge the battery having the samecapacity in a shorter time.

The first charging mode can be a normal charging mode and the secondcharging mode can be a quick charging mode. Under the normal chargingmode, the adapter outputs a relatively small current (typically lessthan 2.5 A) or charges the battery in the device to be charged with arelatively small power (typically less than 15 W). In the normalcharging mode, it may take several hours to fully charge a largercapacity battery (such as a battery with 3000 mAh). In contrast, underthe quick charging mode, the adapter can output a relatively largecurrent (typically greater than 2.5 A, such as 4.5 A, 5 A or higher) orcharges the battery in the device to be charged with a relatively largepower (typically greater than or equal to 15 W). Compared to the normalcharging mode, the charging speed of the adapter in the quick chargingmode is faster, and the charging time required for fully charging abattery with the same capacity in the quick charging mode may besignificantly shortened.

As illustrated in FIG. 8, the charging interface 11 may include a datawire, and the device to be charged 10 may further include a control unit71. The control unit 71 may perform a bidirectional communication withthe adapter via the data wire so as to control the output of the adapterin the second charging mode. For example, the charging interface is theUSB interface, and the data wire may be D+ wire and/or D-wire in the USBinterface.

The content communicated between the control unit 71 and the adapter isnot limited in embodiments of the present disclosure, and the controlmethod of the control unit 71 in the second charging mode is also notlimited in embodiments of the present disclosure. For example, thecontrol unit 71 may communicate with the adapter to obtain the presenttotal voltage or present total electric quantity of the plurality ofbattery cells 13 in the device to be charged, and adjust the outputvoltage or output current of the adapter based on the present totalvoltage or present total electric quantity of the plurality of batterycells 13. In the following, the content communicated between the controlunit 71 and the adapter and the control manner of the control unit 71 onthe output of the adapter in the second charging mode will be describedin detail in combination with specific embodiments.

The master-slave relation of the adapter and the device to be charged(or the control unit 71 in the device to be charged) is not limited inembodiments of the present disclosure. In other words, any of theadapter and the device to be charged can be configured as the masterdevice initiating the bidirectional communication session, accordingly,the other one can be configured as the slave device making a firstresponse or a first reply to the communication initiated by the masterdevice. As a feasible implementation, during the communication, theidentifications of the master device and the slave device can bedetermined by comparing the electrical levels of the adapter and thedevice to be charged relative to the ground.

The specific implementation of the bidirectional communication betweenthe adapter and the device to be charged is not limited in embodimentsof the present disclosure. In other words, any of the adapter and thedevice to be charged can be configured as the master device initiatingthe bidirectional communication session, accordingly, the other one canbe configured as the slave device making a first response or a firstreply to the communication initiated by the master device, and themaster device is able to make a second response to the first response orthe first reply of the slave device, and thus a negotiation about acharging mode can be realized between the master device and the slavedevice. As a feasible implementation, a charging operation between themaster device and the slave device is performed after a plurality ofnegotiations about the charging mode are completed between the masterdevice and the slave device, such that the charging process can beperformed safely and reliably after the negotiation.

As an implementation, the mater device is able to make a second responseto the first response or the first reply made by the slave device withregard to the communication session in a manner that, the master deviceis able to receive the first response or the first reply made by theslave device to the communication session and to make a targeted secondresponse to the first response or the first reply. As an example, whenthe master device receives the first response or the first reply made bythe slave device to the communication session in a predetermined timeperiod, the master device makes the targeted second response to thefirst response or the first reply of the slave device in a manner that,the master device and the slave device complete one negotiation aboutthe charging mode, and a charging process may be performed between themaster device and the salve device in the first charging mode or thesecond charging mode according to a negotiation result, i.e., theadapter charges the device to be charged in the first charging mode orthe second charging mode according to a negotiation result.

As another implementation, the mater device is able to make a secondresponse to the first response or the first reply made by the slavedevice to the communication session in a manner that, when the masterdevice does not receive the first response or the first reply made bythe slave device to the communication session in the predetermined timeperiod, the mater device also makes the targeted second response to thefirst response or the first reply of the slave device. As an example,when the master device does not receive the first response or the firstreply made by the slave device to the communication session in thepredetermined time period, the mater device makes the targeted secondresponse to the first response or the first reply of the slave device ina manner that, the master device and the slave device complete onenegotiation about the charging mode, the charging process is performedbetween the mater device and the slave device in the first chargingmode, i.e., the adapter charges the device to be charged in the firstcharging mode.

In some embodiments, when the device to be charged is configured as themater device initiating the communication session, after the adapterconfigured as the slave device makes the first response or the firstreply to the communication session initiated by the master device, it isunnecessary for the device to be charged to make the targeted secondresponse to the first response or the first reply of the adapter, i.e.,one negotiation about the charging mode is regarded as completed betweenthe adapter and the device to be charged, and the adapter is able tocharge the device to be charged in the first charging mode or the secondcharging mode according to the negotiation result.

In some embodiments, the control unit 71 performs the bidirectionalcommunication with the adapter via the data wire to control the outputof the adapter in the second charging mode as follows. The control unit71 performs the bidirectional communication with the adapter tonegotiate the charging mode between the adapter and the device to becharged.

In some embodiments, the control unit 71 performs the bidirectionalcommunication with the adapter to negotiate the charging mode betweenthe adapter and the device to be charged as follows. The control unit 71receives a first instruction sent by the adapter, in which the firstinstruction is configured to query the device to be charged whether tooperate in the second charging mode. The control unit 71 sends a replyinstruction of the first instruction to the adapter, in which the replyinstruction of the first instruction is configured to indicate whetherthe device to be charged agrees to operate in the second the adapter, tofeedback the p 71 controls the adapter to charge the plurality ofbattery cells via the first charging circuit 12 when the device to becharged agrees to operate in the second charging mode.

In some embodiments, the control unit 71 performs the bidirectionalcommunication with the adapter via the data wire to control the outputof the adapter in the second charging mode as follows. The control unit71 performs the bidirectional communication with the adapter todetermine a charging voltage outputted by the adapter in the secondcharging mode for charging the device to be charged.

In some embodiments, the control unit 71 performs the bidirectionalcommunication with the adapter to determine the charging voltageoutputted by the adapter in the second charging mode for charging thedevice to be charged as follows. The control unit 71 receives a secondinstruction sent by the adapter, in which the second instruction isconfigured to query whether the output voltage of the adapter matcheswith the current total voltage of the plurality of battery cells 13 ofthe device to be charged. The control unit 71 sends a reply instructionof the second instruction to the adapter, in which the reply instructionof the second instruction is configured to indicate that the outputvoltage of the adapter matches with the present total voltage of theplurality of battery cells, or is higher or lower than the present totalvoltage of the plurality of battery cells. In another embodiment, thesecond instruction can be configured to query whether the present outputvoltage of the adapter is suitable for being used as the chargingvoltage outputted by the adapter in the second charging mode forcharging the device to be charged, and the reply instruction of thesecond instruction can be configured to indicate the present outputvoltage of the adapter is suitable, high or low. When the present outputvoltage of the adapter is suitable for the present total voltage of theplurality of battery cells or the present output voltage of the adapteris suitable for being used as the charging voltage outputted by theadapter in the second charging mode for charging the device to becharged, it indicates that the present output voltage of the adapter isslightly higher than the present total voltage of the plurality ofbattery cells, and a difference between the output voltage of theadapter and the present total voltage of the plurality of battery cellsis within a predetermined range (typically in an order of hundreds ofmillivolts).

In some embodiments, the control unit 71 may perform the bidirectionalcommunication with the adapter via the data wire to control the outputof the adapter in the second charging mode as follows. The control unit71 performs the bidirectional communication with the adapter todetermine the charging current outputted by the adapter in the secondcharging mode for charging the device to be charged.

In some embodiments, the control unit 71 performs the bidirectionalcommunication with the adapter to determine the charging currentoutputted by the adapter in the second charging mode for charging thedevice to be charged as follows. The control unit 71 receives a thirdinstruction sent by the adapter, in which the third instruction isconfigured to query the maximum charging current presently supported bythe device to be charged. The control unit 71 sends a reply instructionof the third instruction to the adapter, in which the reply instructionof the third instruction is configured to indicate the maximum chargingcurrent presently supported by the device to be charged, such that theadapter determines the charging current outputted by the adapter in thesecond charging mode for charging the device to be charged based on themaximum charging current presently supported by the device to becharged. In an embodiment, the control unit 71 can determine thecharging current outputted by the adapter in the second charging modefor charging the device to be charged based on the maximum chargingcurrent presently supported by the device to be charged in many ways.For example, the adapter can determine the maximum charging currentpresently supported by the device to be charged as the charging currentoutputted by the adapter in the second charging mode for charging thedevice to be charged, or can determine the charging current outputted bythe adapter in the second charging mode for charging the device to becharged after comprehensively considering the maximum charging currentpresently supported by the device to be charged and its own currentoutput capability.

In some embodiments, the control unit 71 may perform the bidirectionalcommunication with the adapter via the data wire to control the outputof the second adapter in the second charging mode as follows. During acharging process using the second charging mode, the control unit 71performs the bidirectional communication with the adapter to adjust theoutput current of the adapter.

In some embodiments, the control unit 71 performs the bidirectionalcommunication with the adapter to adjust the output current of theadapter as follows. The control unit 71 receives a fourth instructionsent by the adapter, in which the fourth instruction is configured toquery a present total voltage of the plurality of battery cells. Thecontrol unit 71 sends a reply instruction of the fourth instruction tothe adapter, in which the reply instruction of the fourth instruction isconfigured to indicate the present total voltage of the plurality ofbattery cells, such that the adapter adjusts the output current of theadapter according to the present total voltage of the plurality ofbattery cells.

In some embodiments, the control unit 71 is further configured toreceive a fifth instruction sent by the adapter. The fifth instructionis configured to indicate that the charging interface 11 is in poorcontact.

Referring to FIG. 9, the communication procedure between the adapter andthe device to be charged (which can be executed by the control unit inthe device to be charged) will be described in detail. Examples in FIG.9 are merely used to help those skilled in the related art to understandthe present disclosure. The embodiments shall not be limited to thespecific numeric values or specific scenes. Apparently, variousmodifications and equivalents can be made by those skilled in therelated art based on examples in FIG. 9, and those modifications andequivalents shall fall within the protection scope of the presentinvention.

As illustrated in FIG. 9, the communication procedure between theadapter and the device to be charged (or called as a communicationprocedure of a quick charging process) may include the following fivestages.

Stage 1:

After the device to be charged is coupled with a power supply providingdevice, the device to be charged may detect a type of the power supplyproviding device via the data wires D+ and D−. When detecting that thepower supply providing device is an adapter, the device to be chargedmay absorb a current greater than a predetermined current threshold I2,such as 1 A. When the adapter detects that a current outputted by theadapter is greater than or equal to I2 within a predetermined timeperiod (such as a continuous time period T1), the adapter determinesthat the device to be charged has completed the recognition of the typeof the power supply providing device. The adapter initiates anegotiation between the adapter and the device to be charged, and sendsan instruction 1 (corresponding to the above-mentioned firstinstruction) to the device to be charged to query whether the device tobe charged agrees that the adapter charges the device to be charged inthe second charging mode.

When the adapter receives a reply instruction from the device to becharged and the reply instruction indicates that the device to becharged disagrees that the adapter charges the device to be charged inthe second charging mode, the adapter detects the output current of theadapter again. When the output current of the adapter is still greaterthan or equal to I2 within a predetermined continuous time period (suchas a continuous time period T1), the adapter sends the instruction 1again to the device to be charged to query whether device to be chargedagrees that the adapter charges the device to be charged in the secondcharging mode. The adapter repeats the above actions in stage 1, untilthe device to be charged agrees that the adapter charges the device tobe charged in the second charging mode or the output current of theadapter is no longer greater than or equal to I2.

After the device to be charged agrees the adapter to charge the deviceto be charged in the second charging mode, the communication procedureproceeds to stage 2.

Stage 2:

For the output voltage of the adapter, there may be several levels. Theadapter sends an instruction 2 (corresponding to the above-mentionedsecond instruction) to the device to be charged to query whether theoutput voltage of the adapter is suitable for the present voltage of thebattery (the present total voltage of the plurality of battery cells) inthe device to be charged.

The device to be charged sends a reply instruction of the instruction 2to the adapter, for indicating that the output voltage of the adapter ishigher, lower or suitable for the present voltage of the battery in thedevice to be charged (the present total voltage of the plurality ofbattery cells). When the reply instruction of the instruction 2indicates that the output voltage of the adapter is higher, or lower,the adapter adjusts the output voltage of the adapter by one level, andsends the instruction 2 to the device to be charged again to querywhether the output voltage of the adapter is suitable for the presentvoltage of the battery (the present total voltage of the plurality ofbattery cells). The above actions in stage 2 are repeated, until thedevice to be charged determines that the output voltage of the adapteris suitable for the present voltage of the battery (the present totalvoltage of the plurality of battery cells). Then, the communicationprocedure proceeds to stage 3.

Stage 3:

The adapter sends an instruction 3 (corresponding to the above-mentionedthird instruction) to the device to be charged to query the maximumcharging current presently supported by the device to be charged. Thedevice to be charged sends a reply instruction of the instruction 3 tothe adapter for indicating the maximum charging current presentlysupported by the device to be charged to the adapter, and then thecommunication procedure proceeds to stage 4.

Stage 4:

The adapter determines the charging current outputted by the adapter inthe second charging mode for charging the device to be charged,according to the maximum charging current presently supported by thedevice to be charged. Then, the communication procedure proceeds tostage 5, i.e., the constant current charging stage.

Stage 5:

When the communication procedure proceeds to the constant currentcharging stage, the adapter sends an instruction 4 (corresponding to theabove-mentioned fourth instruction) to the device to be charged atintervals to query the present voltage of the battery (the present totalvoltage of the plurality of battery cells) in the device to be charged.The device to be charged may send a reply instruction of the instruction4 to the adapter, to feedback the present voltage of the battery (thepresent total voltage of the plurality of battery cells). The adaptermay determine according to the present voltage of the battery (thepresent total voltage of the plurality of battery cells) whether thecharging interface is in poor contact and whether it is necessary tostep down the output current of the adapter. When the adapter determinesthat the charging interface is in poor contact, the adapter sends aninstruction 5 (corresponding to the above-mentioned fifth instruction)to the device to be charged, and the adapter quits the second chargingmode and then the communication procedure is reset and proceeds to stage1 again.

In some embodiments of the present disclosure, in stage 1, when thedevice to be charged sends the reply instruction of the instruction 1,the reply instruction of the instruction 1 may carry data (orinformation) of the path impedance of the device to be charged. The dataof the path impedance of the device to be charged may be used in stage 5to determine whether the charging interface is in poor contact.

In some embodiments of the present disclosure, in stage 2, the timeperiod from when the device to be charged agrees that the adaptercharges the device to be charged in the second charging mode to when theadapter adjusts the output voltage of the adapter to a suitable valuemay be controlled in a certain range. If the time period exceeds apredetermined range, the adapter or the device to be charged maydetermine that the communication procedure is abnormal, and is reset andproceeds to stage 1.

In some embodiments, in stage 2, when the output voltage of the adapteris higher than the present voltage of the battery (the present totalvoltage of the plurality of battery cells) by ΔV (ΔV may be set to200-500 mV), the device to be charged may send a reply instruction ofthe instruction 2 to the adapter, for indicating that the output voltageof the adapter is suitable for the voltage of the battery (the totalvoltage of the plurality of battery cells) in the device to be charged.

In some embodiments of the present disclosure, in stage 4, the adjustingspeed of the output current of the adapter may be controlled to be in acertain range, thus avoiding an abnormity occurring in the chargingprocess due to a too fast adjusting speed.

In some embodiments of the present disclosure, in stage 5, the variationdegree of the output current of the adapter may be controlled to be lessthan 5%.

In some embodiments of the present disclosure, in stage 5, the adaptercan monitor the path impedance of a charging circuit in real time. Indetail, the adapter can monitor the path impedance of the chargingcircuit according to the output voltage of the adapter, the outputcurrent of the adapter and the present voltage of the battery (thepresent total voltage of the plurality of battery cells) fed back by thedevice to be charged. When the path impedance of the charging circuit isgreater than a sum of the path impedance of the device to be charged andthe impedance of a charging wire, it may be considered that the charginginterface is in poor contact, and thus the adapter stops charging thedevice to be charged in the second charging mode.

In some embodiments of the present disclosure, after the adapter startsto charge the device to be charged in the second charging mode, timeintervals of communication between the adapter and the device to becharged may be controlled to be in a certain range, thus avoidingabnormity in the communication procedure due to a too short timeinterval of communication.

In some embodiments of the present disclosure, the stop of a chargingprocess (or the stop of the charging process that the adapter chargesthe device to be charged in the second charging mode) may be arecoverable stop or an unrecoverable stop.

For example, when it is detected that the battery (the plurality ofbattery cells) in the device to be charged is fully charged or thecharging interface is in poor contact, the charging process is stoppedand the charging communication procedure is reset, and the chargingprocess proceeds to stage 1 again. When the device to be chargeddisagrees that the adapter charges the device to be charged in thesecond charging mode, the communication procedure would not proceed tostage 2. The stop of the charging process in this case may be regardedas an unrecoverable stop.

For another example, when an abnormity occurs in the communicationbetween the adapter and the device to be charged, the charging processis stopped and the charging communication procedure is reset, and thecharging process proceeds to stage 1 again. After requirements for stage1 are met, the device to be charged agrees that the adapter charges thedevice to be charged in the second charging mode to recover the chargingprocess. In this case, the stop of the charging process may beconsidered as a recoverable stop.

For another example, when the device to be charged detects that anabnormity occurs in the battery (the plurality of battery cells), thecharging process is stopped and reset, and the charging process proceedsto stage 1 again. The device to be charged disagrees that the adaptercharges the device to be charged in the second charging mode. When thebattery (the plurality of battery cells) returns to normal and therequirements for stage 1 are met, the device to be charged agrees thatthe adapter charges the device to be charged in the second chargingmode. In this case, the termination of quick charging process may beconsidered as a recoverable termination.

Communication actions or operations illustrated in FIG. 9 are merelyexemplary. For example, in stage 1, after the device to be charged iscoupled with the adapter, the handshake communication between the deviceto be charged and the adapter may be initiated by the device to becharged. In other words, the device to be charged sends an instruction 1to query the adapter whether to operate in the second charging mode.When the device to be charged receives a reply instruction indicatingthat the adapter agrees to charge the device to be charged in the secondcharging mode from the adapter, the adapter starts to charge the battery(the plurality of battery cells) in the device to be charged in thesecond charging mode.

For another example, after stage 5, there may be a constant voltagecharging stage. In detail, in stage 5, the device to be charged mayfeedback the present voltage of the battery (the present total voltageof the plurality of battery cells) to the adapter. The charging processproceeds to the constant voltage charging stage from the constantcurrent charging stage when the present voltage of the battery (thepresent total voltage of the plurality of battery cells) reaches avoltage threshold for constant voltage charging. During the constantcurrent charging stage, the charging current steps down gradually. Whenthe current reduces to a certain threshold, it indicates that thebattery (the plurality of battery cells) in the device to be charged isfully charged, and thus the charging process is stopped.

The device embodiments of the present disclosure are described above indetail with reference to FIGS. 1-9. The method embodiments of thepresent disclosure will be described below in detail with reference toFIG. 10. The description of the method embodiments corresponds to thedescription of the device embodiments, which are not elaborated hereinfor simplicity.

FIG. 10 is a flow chart of a charging method according to embodiments ofthe present disclosure. The charging method illustrated in FIG. 10 maybe applied for charging the device to be charged. The device to becharged includes a charging interface.

The charging method illustrated in FIG. 10 may include the followings.

At block 910, an output voltage and an output current of an adapter arereceived via the charging interface.

At block 920, the output voltage and the output current of the adapterare directly applied to both ends of a plurality of battery cellscoupled in series in the device to be charged, so as to perform a directcharging on the plurality of battery cells.

In some embodiments, the charging method may further include: supplyingpower to elements in the device to be charged based on a voltage of asingle battery cell in the plurality of battery cells, in which thesingle battery cell may be any one of the plurality of battery cells.

In some embodiments, the charging method may further include: equalizingvoltages of respective ones of the plurality of battery cells.

In some embodiments, the plurality of battery cells include a firstbattery cell and a second battery cell, and equalizing voltages ofrespective cells of the plurality of battery cells includes:transferring electric quantity between the first battery cell and thesecond battery cell in an electromagnetic coupling manner.

In some embodiments, transferring electric quantity between the firstbattery cell and the second battery cell in an electromagnetic couplingmanner includes: coupling energy outputted by the first battery cell toa second circuit in an electromagnetic coupling manner through a firstcircuit, generating a first charging current according to the energyfrom the first circuit through the second circuit, and charging thefirst battery cell and the second battery cell with the first chargingcurrent. The first circuit is coupled with the first battery cell, andthe second circuit is coupled with the first battery cell and the secondbattery cell respectively.

In some embodiments, transferring electric quantity between the firstbattery cell and the second battery cell in an electromagnetic couplingmanner as illustrated in FIG. 10 may further includes: coupling energyoutputted by the second battery cell to the second circuit in anelectromagnetic coupling manner through a third circuit; generating asecond charging current according to the energy from the third circuitthrough the second circuit, and charging the first battery cell and thesecond battery cell with the second charging current.

In some embodiments, transferring electric quantity between the firstbattery cell and the second battery cell in an electromagnetic couplingmanner as illustrated in FIG. 10 further includes: coupling energyoutputted by the first battery cell and the second battery cell to afifth circuit in an electromagnetic coupling manner through a fourthcircuit; generating a second charging current according to the energyfrom the fourth circuit through the fifth circuit, and charging thefirst battery cell with the second charging current. The fourth circuitis coupled with the first battery cell and the second battery cellrespectively, and the fifth circuit is coupled with the first batterycell.

In some embodiments, the charging method of FIG. 10 may furtherincludes: coupling energy outputted by the first battery cell and thesecond battery cell to a sixth circuit in an electromagnetic couplingmanner through the fourth circuit; generating a third charging currentaccording to the energy from the fourth circuit through the sixthcircuit, and charging the second battery cell with the third chargingcurrent.

In some embodiments, the charging method of FIG. 10 may further include:step-up the output voltage of the adapter to a second voltage; andapplying the second voltage to both ends of the plurality of batterycells so as to charge the plurality of battery cells. The second voltageis greater than a total voltage of the plurality of battery cells.

In some embodiments, the adapter supports a first charging mode and asecond charging mode, in which a charging speed of the adapter in thesecond charging mode is greater than that of the adapter in the firstcharging mode.

In some embodiments, the charging interface includes a data wire. Thecharging method of FIG. 10 may further include: performing abidirectional communication with the adapter via the data wire tocontrol an output of the adapter in the second charging mode.

In some embodiments, performing the bidirectional communication with theadapter via the data wire to control the output of the adapter in thesecond charging mode includes: performing the bidirectionalcommunication with the adapter to negotiate about a charging modebetween the adapter and the device to be charged.

In some embodiments, performing the bidirectional communication with theadapter to negotiate about the charging mode between the adapter and thedevice to be charged includes: receiving a first instruction sent by theadapter, in which the first instruction is configured to query thedevice to be charged whether to operate in the second charging mode;sending a reply instruction of the first instruction to the adapter, inwhich the reply instruction of the first instruction is configured toindicate whether the device to be charged agrees to operate in thesecond charging mode; and controlling the adapter to charge theplurality of battery cells via the first charging circuit when thedevice to be charged agrees to operate in the second charging mode.

In some embodiments, performing the bidirectional communication with theadapter via the data wire to control the output of the adapter in thesecond charging mode may include: performing the bidirectionalcommunication with the adapter to determine a charging voltage outputtedby the adapter in the second charging mode for charging the device to becharged.

In some embodiments, performing the bidirectional communication with theadapter to determine the charging voltage outputted by the adapter inthe second charging mode for charging the device to be charged mayinclude: receiving a second instruction sent by the adapter, in whichthe second instruction is configured to query whether the output voltageof the adapter matches with a present total voltage of the plurality ofbattery cells; and sending a reply instruction of the second instructionto the adapter, in which the reply instruction of the second instructionis configured to indicate that the output voltage of the adapter matcheswith the present total voltage of the plurality of battery cells, or ishigher or lower than the present total voltage of the plurality ofbattery cells.

In some embodiments, performing the bidirectional communication with theadapter via the data wire to control the output of the adapter in thesecond charging mode may include: performing the bidirectionalcommunication with the adapter to determine a charging current outputtedby the adapter in the second charging mode for charging the device to becharged.

In some embodiments, performing the bidirectional communication with theadapter to determine the charging current outputted by the adapter inthe second charging mode for charging the device to be charged mayinclude: receiving a third instruction sent by the adapter, in which thethird instruction is configured to query the maximum charging currentpresently supported by the device to be charged; and sending a replyinstruction of the third instruction to the adapter, in which the replyinstruction of the third instruction is configured to indicate themaximum charging current presently supported by the device to becharged, such that the adapter determines the charging current outputtedby the adapter in the second charging mode for charging the device to becharged according to the maximum charging current presently supported bythe device to be charged.

In some embodiments, performing the bidirectional communication with theadapter via the data wire to control the output of the adapter in thesecond charging mode may include: performing the bidirectionalcommunication with the adapter to adjust the output current of theadapter, during a charging process in the second charging mode.

In some embodiments, performing the bidirectional communication with theadapter to adjust the output current of the adapter may include:receiving a fourth instruction sent by the adapter, in which the fourthinstruction is configured to query a present total voltage of theplurality of battery cells; and sending a reply instruction of thefourth instruction to the adapter, in which the reply instruction of thefourth instruction is configured to indicate the present total voltageof the plurality of battery cells, such that the adapter adjusts theoutput current of the adapter according to the present total voltage ofthe plurality of battery cells.

Those skilled in the art may be aware that, in combination with theexamples described in the embodiments disclosed in this specification,units and algorithm steps can be implemented by electronic hardware, ora combination of computer software and electronic hardware. In order toclearly illustrate interchangeability of the hardware and software,components and steps of each example are already described in thedescription according to the function commonalities. Whether thefunctions are executed by hardware or software depends on particularapplications and design constraint conditions of the technicalsolutions. Persons skilled in the art may use different methods toimplement the described functions for each particular application, butit should not be considered that the implementation goes beyond thescope of the present invention.

Those skilled in the art may be aware that, with respect to the workingprocess of the system, the device and the unit, reference is made to thepart of description of the method embodiment for simple and convenience,which are described herein.

In embodiments of the present disclosure, it should be understood that,the disclosed system, device and method may be implemented in other way.For example, embodiments of the described device are merely exemplary.The partition of units is merely a logical function partitioning. Theremay be other partitioning ways in practice. For example, several unitsor components may be integrated into another system, or some featuresmay be ignored or not implemented. Further, the coupling between eachother or directly coupling or communication connection may beimplemented via some interfaces. The indirect coupling or communicationconnection may be implemented in electrical, mechanical or othermanners.

In embodiments of the present disclosure, it should be understood that,the units illustrated as separate components can be or not be separatedphysically, and components described as units can be or not be physicalunits, i.e., can be located at one place, or can be distributed ontomultiple network units. It is possible to select some or all of theunits according to actual needs, for realizing the objective ofembodiments of the present disclosure.

In addition, each functional unit in the present disclosure may beintegrated in one progressing module, or each functional unit exists asan independent unit, or two or more functional units may be integratedin one module.

If the integrated module is embodied in software and sold or used as anindependent product, it can be stored in the computer readable storagemedium. Based on this, the technical solution of the present disclosureor a part making a contribution to the related art or a part of thetechnical solution may be embodied in a manner of software product. Thecomputer software produce is stored in a storage medium, including someinstructions for causing one computer device (such as a personal PC, aserver, or a network device etc.) to execute all or some of steps of themethod according to embodiments of the present disclosure. Theabove-mentioned storage medium may be a medium able to store programcodes, such as, USB flash disk, mobile hard disk drive (mobile HDD),read-only memory (ROM), random-access memory (RAM), a magnetic tape, afloppy disc, an optical data storage device, and the like.

1. A device to be charged, comprising: a charging interface; and a firstcharging circuit, coupled with the charging interface, configured toreceive an output voltage and an output current of an adapter via thecharging interface and to directly apply the output voltage and theoutput current of the adapter to both ends of a plurality of batterycells coupled in series in the device to be charged, so as to perform adirect charging on the plurality of battery cells.
 2. The device to becharged according to claim 40, wherein the plurality of battery cellscomprise a first battery cell and a second battery cell, and theequalization circuit is configured to transfer electric quantity betweenthe first battery cell and the second battery cell in an electromagneticcoupling manner.
 3. The device to be charged according to claim 2,wherein the equalization circuit comprises a first circuit and a secondcircuit, the first circuit is coupled with the first battery cell, andthe second circuit is coupled with the first battery cell and the secondbattery cell respectively; wherein when the first circuit is switchedon, the first circuit is configured to couple energy outputted by thefirst battery cell to the second circuit in an electromagnetic couplingmanner, such that the second circuit generates a first charging currentbased on the energy from the first circuit, and charges the firstbattery cell and the second battery cell with the first chargingcurrent.
 4. The device to be charged according to claim 3, wherein theequalization circuit further comprises a third circuit, and the thirdcircuit is coupled with the second battery cell; wherein when the thirdcircuit is switched on, the third circuit is configured to couple energyoutputted by the second battery cell to the second circuit in anelectromagnetic coupling manner, such that the second circuit generatesa second charging current based on the energy from the third circuit,and charges the first battery cell and the second battery cell with thesecond charging current.
 5. The device to be charged according to claim2, wherein the equalization circuit comprises a fourth circuit and afifth circuit, the fourth circuit is coupled with the first battery celland the second battery cell respectively, and the fifth circuit iscoupled with the first battery cell; wherein when both the fourthcircuit and the fifth circuit are switched on, the fourth circuit isconfigured to couple energy outputted by the first battery cell and thesecond battery cell to the fifth circuit in an electromagnetic couplingmanner, such that the fifth circuit generates a second charging currentbased on the energy from the fourth circuit, and charges the firstbattery cell with the second charging current.
 6. The device to becharged according to claim 5, wherein the equalization circuit furthercomprises a sixth circuit, and the sixth circuit is coupled with thesecond battery cell; wherein when both the fourth circuit and the sixthcircuit are switched on, the fourth circuit is configured to coupleenergy outputted by the first battery cell and the second battery cellto the sixth circuit in an electromagnetic coupling manner, such thatthe sixth circuit generates a third charging current based on the energyfrom the fourth circuit, and charges the second battery cell with thethird charging current.
 7. The device to be charged according to claim1, further comprising: a power supply circuit, having an input endcoupled with both ends of an arbitrary battery cell in the plurality ofbattery cells, and configured to supply power for elements in the deviceto be charged based on a voltage of the arbitrary battery cell. 8.(canceled)
 9. The device to be charged according to claim 1, wherein theoutput voltage outputted by the adapter and received by the firstcharging circuit via the charging interface is a voltage outputted bythe adapter in a constant current mode, and the output current outputtedby the adapter and received by the first charging circuit via thecharging interface is a current outputted by the adapter in the constantcurrent mode.
 10. The device to be charged according to claim 1, furthercomprising: a second charging circuit, comprising a step-up circuit, thestep-up circuit having both ends coupled with the charging interface andthe plurality of battery cells respectively and configured to receivethe output voltage of the adapter via the charging interface, to step upthe output voltage of the adapter to a second voltage and to apply thesecond voltage to the both ends of the plurality of battery cells so asto charge the plurality of battery cells, wherein the output voltage ofthe adapter received by the second charging circuit is less than a totalvoltage of the plurality of battery cells, and the second voltage isgreater than the total voltage.
 11. (canceled)
 12. The device to becharged according to claim 10, wherein the adapter supports a firstcharging mode and a second charging mode, a charging speed of theadapter in the second charging mode is greater than that of the adapterin the first charging mode, the adapter charges the plurality of batterycells via the second charging circuit in the first charging mode, andcharges the plurality of battery cells via the first charging circuit inthe second charging mode.
 13. The device to be charged according toclaim 12, wherein the charging interface comprises a data wire, thedevice to be charged further comprises a control unit, and the controlunit is configured to perform a bidirectional communication with theadapter via the data wire to control an output of the adapter in thesecond charging mode.
 14. The device to be charged according to claim13, wherein when the control unit performs the bidirectionalcommunication with the adapter via the data wire to control the outputof the adapter in the second charging mode, the control unit isconfigured to perform the bidirectional communication with the adapterto negotiate about a charging mode between the adapter and the device tobe charged.
 15. The device to be charged according to claim 14, whereinwhen the control unit performs the bidirectional communication with theadapter to negotiate about the charging mode between the adapter and thedevice to be charged, the control unit is configured to: receive a firstinstruction sent by the adapter, in which the first instruction isconfigured to query the device to be charged whether to operate in thesecond charging mode; send a reply instruction of the first instructionto the adapter, in which the reply instruction of the first instructionis configured to indicate whether the device to be charged agrees tooperate in the second charging mode; control the adapter to charge theplurality of battery cells via the first charging circuit when thedevice to be charged agrees to operate in the second charging mode. 16.The device to be charged according to claim 13, wherein when the controlunit performs the bidirectional communication with the adapter via thedata wire to control the output of the adapter in the second chargingmode, the control unit is configured to perform the bidirectionalcommunication with the adapter to determine a charging voltage outputtedby the adapter in the second charging mode for charging the device to becharged.
 17. The device to be charged according to claim 16, whereinwhen the control unit performs the bidirectional communication with theadapter to determine the charging voltage outputted by the adapter inthe second charging mode for charging the device to be charged, thecontrol unit is configured to: receive a second instruction sent by theadapter, in which the second instruction is configured to query whetherthe output voltage of the adapter matches with a present total voltageof the plurality of battery cells; send a reply instruction of thesecond instruction to the adapter, in which the reply instruction of thesecond instruction is configured to indicate that the output voltage ofthe adapter matches with the present total voltage of the plurality ofbattery cells, or is higher or lower than the present total voltage ofthe plurality of battery cells.
 18. The device to be charged accordingto claim 13, wherein when the control unit performs the bidirectionalcommunication with the adapter via the data wire to control the outputof the adapter in the second charging mode, the control unit isconfigured to perform the bidirectional communication with the adapterto determine a charging current outputted by the adapter in the secondcharging mode for charging the device to be charged; wherein when thecontrol unit performs the bidirectional communication with the adapterto determine the charging current outputted by the adapter in the secondcharging mode for charging the device to be charged, the control unit isconfigured to: receive a third instruction sent by the adapter, in whichthe third instruction is configured to query a maximum charging currentpresently supported by the device to be charged; send a replyinstruction of the third instruction to the adapter, in which the replyinstruction of the third instruction is configured to indicate themaximum charging current presently supported by the device to becharged, such that the adapter determines the charging current outputtedby the adapter in the second charging mode for charging the device to becharged according to the maximum charging current presently supported bythe device to be charged.
 19. (canceled)
 20. The device to be chargedaccording to claim 13, wherein when the control unit performs thebidirectional communication with the adapter via the data wire tocontrol the output of the adapter in the second charging mode, thecontrol unit is configured to perform the bidirectional communicationwith the adapter to adjust the output current of the adapter, during acharging process in the second charging mode; wherein when the controlunit performs the bidirectional communication with the adapter to adjustthe output current of the adapter, the control unit is configured to:receive a fourth instruction sent by the adapter, in which the fourthinstruction is configured to query a present total voltage of theplurality of battery cells; send a reply instruction of the fourthinstruction to the adapter, in which the reply instruction of the fourthinstruction is configured to indicate the present total voltage of theplurality of battery cells, such that the adapter adjusts the outputcurrent of the adapter according to the present total voltage of theplurality of battery cells.
 21. (canceled)
 22. A charging method,applied for charging a device to be charged, wherein the device to becharged comprises a charging interface, and the charging methodcomprises: receiving an output voltage and an output current of anadapter via the charging interface; directly applying the output voltageand the output current of the adapter to both ends of a plurality ofbattery cells coupled in series in the device to be charged, so as toperform a direct charging on the plurality of battery cells; andequalizing voltages of respective battery cells of the plurality ofbattery cells. 23.-39. (canceled)
 40. The device to be charged accordingto claim 1, further comprising: an equalization circuit, coupled withthe plurality of battery cells, and configured to equalize voltages ofrespective battery cells of the plurality of battery cells.
 41. A deviceto be charged, further comprising: a charging interface; a secondcharging circuit, comprising a step-up circuit, the step-up circuithaving both ends coupled with the charging interface and the pluralityof battery cells respectively and configured to receive the outputvoltage of the adapter via the charging interface, to step up the outputvoltage of the adapter to a second voltage and to apply the secondvoltage to the both ends of the plurality of battery cells so as tocharge the plurality of battery cells, wherein the output voltage of theadapter received by the second charging circuit is less than a totalvoltage of the plurality of battery cells, and the second voltage isgreater than the total voltage; and an equalization circuit, coupledwith the plurality of battery cells, and configured to equalize voltagesof respective battery cells of the plurality of battery cells.